My general research interests lie in the identification and detailed study of systems in the mammalian brain which regulate species-typical behavior patterns. I have taken as a principal focus the neural regulation of male sexual behavior. Recent evidence, including work done in my laboratory, indicates that the medial forebrain bundle contains elements of at least two systems involved in the normal expression of sexual behavior in the male rat: A medial preoptic (mPOA) - medial forebrain bundle (MFB) system which, when damaged, interferes with the selection or triggering of the copulatory sequence, and one or more of the catecholamine (CA) containing systems which may be involved in the animal's general responsiveness to the approach-eliciting properties of environmental stimuli. The proposed research is designed to study these systems through the use of a converging research strategy combining microknife transection and neurochemical lesion procedures with neurochemical and behavioral analysis. Specifically, I will be asking: (1) whether the sexual deficits which are produced by neurochemical lesions of ascending CA-containing pathways are the result of specific damage to one or more of the CA subsystems (i.e. norepinephrine- or dopamine-containing pathways), and (2) whether the sexual deficit produced by transecting the mPOA-MFB system is due to damaging a specific CA input into the mPOA. We will continue to elaborate on the profiles of behavioral disruption that results from CA or mPOA-MFB lesions and we will begin similar experiments to determine the nature of the sexual impairment produced by another pathway to the anterior hypothalamus and mPOA, involving the stria terminalis and corticomedial amygdala.